WYOMING 
University  of 

Special  Bulletin:  Heating 
Power  of  Wyoming  Coal  &  Oil 


SB  3E  D77 


AGRICULTURAL 
LIBRARY, 

UNIVERSITY 

-~OF— 

CALIFORNIA. 


UNIVERSITY  OF  WYOMING. 

L.IR.AMIE,  WYOMING. 


Departments  of  Chemistry  and  Mechanical  Engineering. 

t'  (J  U 


SPECIAL     BULLETIN. 

JANUARY,  1895. 


The  Heatinn  Power  of  ffyoiof  Coal  and  Oil 

With  a  Description  of  the  Bomb  Calorimeter, 


BY  EDWIN  E.  SLOSSON,  Professor  of  Chemistry,  and  L.  C.  COLBURN, 
Professor  of  Mechanical  Engineering. 


THE  HEATING  POWER 


—OF— 


WYOMING  COAL  AND  OIL 


INTRODUCTORY. 


The  value  of  a  fuel  depends  upon  the  amount  of  heat 
that  can  be  obtained  from  it.  Although  we  buy  it  by 
weight,  it  is  not  matter  we  want,  but  energy.  Everyone 
who  uses  fuel  either  for  heat  or  power  needs  to  know  what 
is  the  greatest  amount  of  heat  that  can  be  obtained  from  the 
kind  of  fuel  used.  He  can  then  tell  whether  he  is  getting 
that  which  is  the  best,  quality  for  the  price  paid  and  also 
whether  he  is  getting  as  large  a  proportion  as  he  should  of 
the  total  heat. 

As  coal  is  at  present  the  most  important  of  the  mineral 
resources  of  Wyoming,  it  was  thought  that  the  State  Uni- 
versity could  hardly  do  a  greater  service  to  consumers  as 
well  as  mine-owners  than  to  make  a  complete  and  impar- 
tial investigation  of  the  relative  and  absolute  value  of  the 
coal  from  different  localities.  We  give  accordingly  a  com- 
parative table  of  the  heating  value  of  Wyoming  coals  so 
far  as  we  could  obtain  samples  of  them,  and  also  a  table 
of  the  fuel  value  of  the  crude  petroleums  of  Wyoming. 
Following  this  is  a  description  of  the  calorimeter  used,  as  it 
is  an  instrument  which  will  probably  come  into  general  use 


R33530 


Wyoming  Coal  and  Oil. 


and,  so  far  as  we  know,  no  complete  description  of  the  ap- 
paratus and  its  manipulation  has  yet  been  published  in  Eng- 
lish.* 

COLLECTION    OF    SAMPLES. 

The  most  essential  part  of  an  investigation  like  the 
present  is  the  selection  of  samples  accurately  representing 
the  coal  fields  from  which  they  are  taken.  This  task  was 
efficiently  performed  by  W.  C.  Knight,  Professor  of  Geol- 
ogy in  the  University  of  Wyoming,  who  personally  vis- 
ited most  of  the  coal-  and  oil-fields  of  the  State  during  the 
summers  of  1893  and  1894. -J-  The  samples  were  obtained 
by  cutting  down  the  whole  face  of  the  exposed  coal-bed,  re- 
jecting partings  and  slates,  breaking  up  and  dividing  until 
a  sample  of  five  to  ten  pounds  weight  was  obtained.  This 
was  shipped  to  the  University,  where  it  was  powdered  and 
sampled  for  analysis.  The  samples  since  their  preparation 
have  been  preserved  in  glass-stoppered  bottles,  and  it  is  be- 
lieved that  they  have  not  materially  lost  in  water  content. 
Samples  not  selected  by  Prof.  Knight  were  usually  taken, 
by  the  owner  or  someone  connected  with  the  management 
and  are  indicated  by  the  letter  O;  for  them,  of  course,  the 
University  assumes  no  responsibility,  although  there  is  no 
reason  to  doubt  the  fairness  of  the  selection.  If  any  import- 
ant coal-mines  have  been  omitted  from  this  investigation  it 
is  not  the  fault  of  the  Universitv,  as  announcements  of  the 
work  in  progress  and  requests  for  samples  have  been  often 
published  during  the  past  two  years. 

*The  best  brief  account  of  thermo-chemical  principles  and  processes 
known  to  the  writers  is  Bertholet's  "Traite  Pratique  dc  Calorimefrie 
C/iiinigite." 

•(•The  coal  samples  obtained  in  1894  were  burned  in  the  freight  car 
in  Laramie. 


Wyoming  Coal  and  Oil.  5 


EXPLANATION    OF  TERMS. 

There  are  so  many  different  units  of  heat  and  energy 
in  use  that  it  was  thought  necessary  to  calculate  results  in 
three  of  the  more  common  forms  to  facilitate  comparison. 

A  calorie  is  the  amount  of  heat  required  to  raise  the 
temperature  of  one  gram  of  water  one  deg.  centigrade.  The 
conception  can,  however,  be  generalized,  and  the  statement 
that  a  gram  of  coal  produces  6,000  cal.  may  be  interpreted  to 
mean  that  the  heat  produced  by  the  combustion  of  one  pound 
ot  coal  would  raise  the  temperature  of  6,000  pounds  of  water 
i  degree  C.  (1.8  Fahrenheit)  or  600  pounds  of  water  10  de- 
grees, etc. 

A  foot-pound  is  the  amount  of  work  required  to  raise 
the  weight  of  one  pound  to  the  height  of  one  foot  against 
the  force  of  gravity.  A  horse-power  is  33,000  foot-pounds 
per  minute,  so  dividing  the  number  of  fool-pounds  per  pound 
by  33,000  will  give  the  number  of  horse-power  developed 
by  burning  a  pound  of  coal  per  minute  Of  course  only  a 
very  small  fraction  of  the  potential  energy  of  the  fuel  can 
be  converted  into  mechanical  energy  by  even  the  most  per- 
fect heat  engines  known. 

The  third  column  gives  the  number  of  pounds  of  water 
which  could  be  evaporated  or  converted  into  steam  by  the 
combustion  of  one  pound  of  the  coal  under  a  pressure  of  one 
atmosphere;  the  water  being  regarded  as  already  heated  to 
the  boiling-point,  100  C.  or  212  Fahr. 

THE    COAL    TESTS. 

The  accompanying  table  gives  all  the  coals  so  far  tested, 
arranged  in  the  order  of  their  heating  value.  The  figures 
given  represent  the  total  amount  of  heat  obtainable  by  per- 
fect combustion.  No  more  heat  can  be  obtained  from  the 


Wyoming  Coal  and  Oil. 


fuel  by  any  method  of  firing;  on  the  contrary,  as  shown 
below,  only  about  half  the  heat  can  be  made  available  in 
steam  production,  and  in  common  practice  a  still  smaller 
proportion  is  usually  obtained.  In  general,  a  larger  propor- 
tion of  the  total  amount  of  heat  can  be  obtained  from  a  good 
coal  than  from  a  poor  one.  In  some  cases,  however,  as 
where  slow  burning  is  required,  a  coal  containing  a  consid- 
erable quantity  of  ash  or  even  water  will  give  better  results 
than  one  of  greater  heating  power  per  ton. 

It  should  be  borne  in  mind  that  the  table  gives  the 
amount  of  heat,  not  the  intensity,  as  that  depends  on  the  rate 
of  combustion.  The  highest  degree  of  heat  attained  in 
these  tests  was  apparently  from  the  pine  knot  which  burned 
so  fiercely  as  to  melt  into  a  ball  the  end  of  a  platinum  rod  of 
1.8  mm.  diameter.  In  one  respect  there  is  an  important 
difference  between  the  conditions  of  combustion  in  the  cal- 
orimeter and  in  the  open  furnace.  In  the  calorimetric  bomb 
the  water  contained  in  the  coal  and  the  gaseous  products  of 
combustion  are  cooled  down  to  the  ordinary  temperature 
while  in  a  furnace  the  steam  and  heated  gases  pass  off.  To 
represent  their  true  relative  value,  therefore,  the  numbers 
given  should  be  reduced  in  proportion  to  the  amount  of 
water  contained.  In  the  case  of  a  coal  giving  6000  calories 
but  containing  10  per  cent,  water  and  four  per  cent,  hydro- 
gen, the  correction  would  be  283  calories  or  about  4.7  per 
cent. 


Wyoming  Coal  and  Oil. 


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TABLE  OF  PROXIMATE  ANALYSES 


—OF- 


WYOMING  COAL 


£  ! 

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NAME  OF   MINE. 

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I 

J.  Curtis,  Ham's  Fork                            i    1.50 

37  -9<>|  57-75 

2.85 

1  OO 

95.65 

2 

Wm.  Goodell,  Ham's  Fork                 !   2.9; 

38.00154.00 

4-°5 

92.00 

3 

A.  Kendall, 

3-75 

37.25155.40 

3.60 

.60 

92.65 

4 

Sweetwater  Mine 

5-55 

36  95  55.70 

1.  80 

.86 

92.65 

5 

Kindt  No.  i 

4.87 

35.68 

55.15 

4-3° 

•77 

90.83 

6 

Van  Dvke  (lower  vein) 

6.25 

56.50 

2-75 

•74 

91.00 

8 

Kindt  No.  2 

5.40135.80 

55  65 

.70 

91-45 

10 

McCoid 

5.05  34.75 

56  15 

4°5 

•85 

90.90 

1  1 

Van  Dyke  (upper  vein) 

5-67 

35-73 

56-85 

i-75 

.68 

92.58 

13 

New  Dillon 

7-2.S 

33-25 

54-25 

4-25 

•50 

87.50 

H 

Rock  Springs  No.  2 

6.22 

3478 

55-75 

325 

1.41 

90.58 

15 

n             "         "     i 

5-38 

3642 

5;.  60 

2.60 

•63 

92.02 

16 

U          4 

595 

34-5  S 

56.10 

3-40 

I.OO 

90.65 

!7 

»«     s 

5-95 

35-7° 

55-75 

•2-55 

•65 

91-45 

18 

it                    «.              u        y 

6-37 

35  *8 

54-85 

36o 

.86 

90.03 

20 

Antelope,  Cambria 

672 

39  38  44.25 

9-65 

3-79 

8363 

21 

Jumbo, 

5-72 

4013 

43.65 

10  50 

457 

83.78 

22 

Red  Canon  No.  6 

7-75 

35-10 

50.60 

6-55 

•29 

85.70 

23 

Carbon  No.  2 

742 

35-43 

48-30 

8.85 

8373 

24 

Rock  Springs  No.  3  (east  face) 

7.17 

3358 

55-6o 

3-65 

.83 

89.18 

26 

Casper  No.  i 

11.30 

32.10 

53-55 

3-20 

.40 

85-65 

27 

Red  Canon  No.  5  (lower  9  feet) 

7.42 

3608 

48.50 

8.00 

•44 

84.58 

28 

Brown 

n.8s 

34-65 

47-30 

6.20 

1.25 

81.9^ 

29 
30 

G.  L.  Young  No.  i 
Almy  No.  7  (upper  vein) 

14.66 

7-37 

31  51 

34-88 

50.85 
48.75 

1.98 

1  9.00 

•56 

8366 

31 

G.  L.  Young  No.  2 

14.64 

36.70 

4645!    2.21 

•48 

83.13 

33 

Meyer,  Carbon                                        I11-1  5 

33-10 

53-00 

2.75 

-65 

83.10 

Wyoming  Coal  and  Oil. 


if 


PROXIMATE   ANALYSES  OF   WYOMING  COALS — Continued. 


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Almy  No.  7  (lower  vein)                         8.8233.5551.75   -5.90 

.65  '85.30 

35 

Mason,  Felix 

10.5037.0248.46      442 

•35  '85.48 

36 
37 
38 
39 
4° 
41 

G.  L.  Young  No.  3 
Lander  Fuel  Co. 
Red  Canon  No.  5  (middle  2j/2  feet) 
Black  Buttes  No'  i 
Gilmore  Mine 
Brown  (1894) 

H-23 
II.4O 

6.8  1 

H-45 
13.12 
11.25 

37.4846.07 

36  6047.60 
36.49147.45 
30.07  51.98 
33.  1  3!  50.40 

36.85  45.00 

2.22 
440 
925 
350 

335 
6.90 

•44 
•5° 

.6, 

83-55 
84.20 

83-94 
82.  os 

83-53 
81.85 

42 

Burgess,  Sheridan 

13.05 

37.5544.70    4--7O 

•71 

82.25 

44 

Harper,  Sundance 

7.88 

33.52  43  90 

14.70 

1.03 

77.40 

45 
46 

47 

Earl  &  Gillis 
Grinnell,  Sheridan 
Deer  Creek,  Glenrock 

13-25 
14.42 
13-82 

34.  2  5  48.00 
33.1844.75 
33.0347.75 

4-50 
7-65 
5-4° 

to 
cr\  co-<r 

M  -<r  p-i 

82.25 

77-93 
80.78 

48 

Inez 

14.65  26.0542.50 

6.80 

.66 

79-  !  5 

49 

51 

52 
53 
54 

Chase 
Bohack 
Becker,  Sheridan 
Holland,  Buffalo 
Monker  &  Mathers,  Buffalo 
Diamond,   Buffalo 

14.50 
13-65 
14.10 

13.55 
14.70 
1450 

345° 
39-25 
35.25 
35-05 
34-30 
33-35 

44-75 
42.60 

38-75 
45-30 
44.20 
44-30 

625 
4-50 
ii  90 
6.10 
6.80 
7-85 

1.03 
.80 
1.04 

•34 
421 

75-25 
81.85 
7400 

80.35 
78.50 

77-65 

NOTE — To  show  in  how  far  the  heating  power  of  coal  is  indicated  bv 
the  ordinary  proximate  analysis  we  give  here  analyses  of  the  same  sam- 
ples in  the  same  order.  These  analyses  are  by  Prof.  Knight  and  have 
many  of  them  been  published  in  Bulletin  No.  14  of  Wyo.  Agricultural 
Experiment  Station.  Nos.  27,  31,  36  and  39  and  all  sulphur  determina- 
tions are  by  E.  E.  Slosson. 


12  Wyoming  Coal  and  Oil. 


EFFICIENCY  OF  BOILERS. 

In  practice  we  find  that  coal  does  not  give  its  theoreti- 
cal evaporation  value.  This  is  caused  by  manv  things  that 
enter  into  the  trial.  Some  of  these  can  he  modified  so  as  to 
produce  higher  results  than  commonly  given. 

Many  coals  split  up  into  fine  particles  when  thrown  di- 
rectly upon  the  incandescent  fuel  upon  the  grate,  and  will 
pass  through  unconsumed.  In  ordinary  methods  of  firing 
the  kindling  is  at  the  bottom  and  the  upper  layers  are  at 
first  only  heated  enough  to  drive  off  the  volatile  parts;  these 
pass  out  of  the  furnace  unconsumed  unless  special  provision 
is  made  to  introduce  fresh  air  to^mingle  with  the  gases  and 
burn  them  as  fuel. 

An  insufficient  supply  of  air  to  the  incandescent  fuel 
will  also  cause  a  loss  that  is  very  great  and  is  usually  whol- 
ly unnoticed;  if  the  fuel  is  burned  to  carbonous  oxide,  CO, 
instead  of  carbonic  acid,  CO2,  the  heat  generated  will  be  on- 
ly 29,000  calories  instead  of  96,960  calories. 

Radiation  and  conduction  of  heat  from  the  boiler  setting 
has  been  considered  as  a  source  of  much  loss;  as  high  as 
24  per  cent,  in  some  cases  has  been  found. 

After  all  precautions  as  to  supply  of  air,  grate  setting 
and  loss  from  radiation  have  been  taken,  the  other  losses 
are  due  largely  to  the  fireman.  One  who  understands  what 
is  taking  place  in  the  furnace  and  applies  his  knowledge 
will  soon  save  in  use  of  fuel  the  increase  of  wages  over  that 
of  a  poor  fireman. 

To  show  the  difference  between  the  theoretical  and 
practical  results  obtained  the  following  data  are  given : 

In  two  tests  made  with  compound  locomotives  by  Geo. 
H.  Barus,  in  April,  May  and  June,  1890:  Coal  giving  a 
calorimeter  test  of  7*634  calories,  by  a  well-planned  sta- 


Coal  and  Oil. 


tionary  boiler  evaporated  11.7  pounds  of  water  (at  and  from 
212  degrees  F.)  In  one  locomotive  7.69  pounds  of  water 
evaporated  and  in  the  other  6.7  pounds  of  water  evaporated. 
This  gives  for  stationary  boiler  82  per  cent,  of  efficiency, 
for  one  locomotive  54  per  cent,  and  the  other  47  per  cent. 
Coals  may  be  divided  into  live  general  classes;  these 
classes  as  collated  by  Scheurer-Kestner  and  others  are  as 
follows: — -j- 


Actual 
calories. 

Boiler    test 
calories. 

Per  cent. 
Realized. 

Drv  or  semi-bituminous    Anthracite 

9,200 
to 

5>76° 
to 

63-9 

9,600 

6,080 

per  cent. 

Short-flaming  caking  or  coking  

9,300 
to 
9,600 

5,888 
'  to 
6,400 

65 
per  cent. 

True  caking  or  cokiii"" 

8,800 

to 

5,376 
to 

62.2 

9.300 

5,888 

per  cent. 

Long-flaming  or  gas  coal 

8,500 

to 

4,864 
to 

58 

8,800 

5<3i2 

per  cent. 

Long-flaming  dry  coals.... 

8,000 
to 

4,288 
to 

55 

8,500 

4,800 

per  cent. 

*An  average  of  8  tests  with  boilers  of  standard  make 
gave  10.45  pounds  of  water  evaporated  per  pound  of  coal. 

An  average  of  104  vertical  boilers  gave  12.24  pounds 
of  water  evaporated  per  pound  of  coal. 

An  average  of  73  horizontal  boilers  gave  11.27  pounds 
of  water  evaporated  per  pound  of  coal. 

These  tests  show  what  we  may  expect  from  an  aver- 
age of  good  coals  under  best  conditions  of  boilers  and  care- 
ful management. 

*Taken  from  Weisbach's  Mechanical  Engineering. 
tKent  in  Mineral  Industry  for  1892.     The  coal  is  calculated  as  free 
from  ash  and  water. 


14.  Wyoming  Coal  and  Oil. 

The  comparisons  would  be  of  more  value  if  the  heating- 
power  of  the  coals  had  been  given. 

In  these  boiler  tests  it  is  shown  that  only  45  per  cent, 
to  85  per  cent,  of  theoretical  evaporation  power  is  obtained 
in  practice. 

In  a  recent  test  made  with  a  Heine  boiler  with  two 
kinds  of  coal  two  results  are  shown:  with  coal  of  6,m  cal- 
ories it  gave  66  per  cent,  efficiency  and  with  coal  of  7,344 
calories  it  gave  76  per  cent,  efficiency. 

If  these  results  be  carefully  studied  it  shows  this  fact 
plainly:  the  better  the  quality  of  the  fuel  the  greater  the  ef- 
ficiency of  the  boiler,  thus  giving  double  results  from  the  use 
of  the  heat  fuel;  not  only  is  there  a  gain  in  amount  of  fuel 
saved  but  also  a  gain  in  efficiency. 

In  the  use  of  Wyoming  coal  for  power  purposes  some- 
what different  management  is  needed  than  with  the  eastern 
coal.  As  they  have  but  little  coking  properties  upon  the 
grate  they  have  a  tendency  to  split  up  into  small  pieces 
and  pass  through  the  bars;  this  is  easily  overcome  by  using 
fine  grate  bars.  The  splitting  up  has  also  a  tendency  to 
cause  smothering  of  the  fire;  this  may  be  prevented  by  hav- 
ing a  wide  dead  plate  in  front  on  to  which  most  of  the  fuel 
is  placed;  here  it  is  gradually  heated  and  the  volatile  parts 
in  passing  off  have  to  pass  over  the  ignited  coal  upon  the 
grate  and  will  be  entirely  consumed,  if  proper  arrangement 
is  made  to  supply  fresh  air.  The  heated  coal  can  then  be 
pushed  back  upon  the  bars. 

Thin  fire-bed  with  frequent  firing  also  gives  best  re- 
sults; regulation  of  draft  is  best  accomplished  with  the  use 
of  a  damper  in  the  stack  rather  than  by  ashpit  and  furnace 
doors. 

With  our  vast  coal-fields  but  little  prospected  and   the 


Wyoming  Coal  and  Oil.  15 

large  yield  of  coal  from  those  already  opened  it  would  seem 
as  if  efforts  to  obtain  highest  efficiency  are  not  necessary, 
but  when  we  consider  that  the  cost  of  fuel  per  ton  is  greater 
than  in  eastern  States,  our  manufacturers  must  bring  down 
the  cost  of  operation  in  every  way  possible  if  they  wish  to 
hold  the  western  market  against  eastern  manufacturers,  and 
this  can  be  done  by  using  the  most  efficient  motive  power 
and  the  best  fuel  they  can  obtain,  when  the  amount  of  actual 
fuel  is  estimated  per  ton  of  coal  purchased. 

With  two  methods  of  obtaining  draught  we  obtain  two 
different  results  from  burning  the  same  kind  of  coal  with 
the  same  boiler.  In  practice  it  is  found  that  more  air  must 
be  supplied  than  is  theoretically  required.  With  natural 
draught  about  24  pounds  of  air  should  be  supplied  per  pound 
of  fuel  used,  while  18  pounds  is  found  sufficient  when  a 
blower  is  used. 

PETROLEUM    AS  FUEL. 

The  use  of  liquid  fuel  is  rapidly  increasing  during  the 
last  three  years,  the  most  notable  example  in  this  country 
being  that  of  the  power  plant  of  the  World's  Fair  at  Chica- 
go; not  being  able  to  obtain  the  official  report  we  can  give 
no  actual  data  as  the  results.  In  Russia  many  of  the  rail- 
roads and  the  steamers  on  the  Black  Sea  are  now  being 
fired  with  petroleum  or  the  heavy  refuse  oils  from  the  re- 
fineries. 

From  the  table  below  it  can  be  seen  that  pound  for 
pound  the  oils  of  Wyoming  possess  nearly  double  the  heat- 
ing capacity  of  the  coals.  -In  the  use  of  oil  for  steaming 
purposes  the  chief  advantages  are:  ease  with  which  firing 
can  be  controlled — simply  turning  a  valve  will  adjust  the 
heat  to  the  desired  degree;  economy  of  storage  room;  free- 
dom from  dirt  and  refuse  from  firing. 


Wyoming  Coal  and  Oil. 


No  complex  apparatus  is  necessary  to  use  oil  as  fuel. 
Any  method  of  reducing  the  oil  to  a  fine  spray  with  either 
air  or  steam  and  of  adjusting  amount  of  air  necessary 
for  combustion  are  all  that  are  required.  This  may  be 
made  by  any  steam-fitter  from  ordinary  steam-pipe  and  fit- 
tings. No  change,  or  but  little,  is  needed  with  boilers  as 
ordinarily  set  to  use  the  oil  as  it  may  be  introduced  into  the 
furnace  through  pipes  that  may  pass  through  the  boiler 
front  or  through  the  sides  of  the  fire-box. 

The  use  of  oil  on  the  railroads  of  Russia  has  proved 
economical  because  fewer  delays  are  caused  in  loading  up 
with  fuel  and  no  fuel  is  needed  while  trains  are  stopping  at 
stations;  the  steam  pressure  can  be  more  easily  controlled 
and  no  steam  is  wasted  at  the  safety  valve.  As  the  Wyo- 
ming oils  are  much  like  the  Russian  oils  the  same  results 
may  be  expected  with  their  use. 

The  use  of  oil  in  iron  manufacture  is  increasing  rapid- 
ly. In  the  Ohio  iron  manufactories  oil  is  considered  cheap- 
er at  2  cts.  per  gallon  than  coal  at  $2.00  per  ton  for  heating 
furnaces  in  making  bolts,  spikes,  chain  and  other  small 
work. 

A  comparative  commercial  test  of  coal  and  oil  for  heat- 
ing is  much  to  be  desired  in  connection  with  calorimeter 
tests.  This  would  show  exactly  the  relative  value  of  the 
two  under  ordinary  conditions. 


WYOMING  PETROLEUM  AND  ASPHALT, 


— 

P 

s 

i  ^  ."^' 

,_  £        -— 

"03  a.  ° 

T3    O 

^  >  *2 

LOCATION. 

MINE. 

a 

§1 

"o  "  M 

0> 

a  5 

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^ 

c 

jo 

o  a 

3  f^  T3 

rt 

cS 

O    *"" 

Of! 

y 

fc  a. 

PH  "S  "S 

i  Petroleum 

Bonanza 

I0.927| 

•:•:-  7              u 

*3 

Shoshone  Reservation 
Salt  Creek,  Natrona  Co. 

10,883  15,204,000 
10,813  15,106,000 

22.24 
2O.  I  I 

*4                        lOil  Mountain, 

Natrona  Co. 

10,747 

*5 
*6 

u             Newcastle,  Weston  Co. 
"              Little  Popo  Agie,           ^ 

Murphv 

10,447 

H.595,000 

19-43 

Fremont  Co.  ^ 

Wells 

10,430 

14,571,000    19.40 

7  Asphalt 

9,532 

*8          "             Wallace  Creek,  west 

of  Garfield  Park 

6,307 

*Collected  by  Prof.  Knight. 


3  — 


1 8  Wyoming  Coal  and  Oil. 

METHODS  OF  DETERMINING  HEATING  POWER. 

There  are  in  use  three  methods  of  estimating-  the  heat- 
ing value  of  fuels:  boiler  tests,  calculation  from  analysis  and 
calorimeter  tests. 

1.  The  boiler  test.      By  using  a   weighed   amount  of 
the  coal  in  question   under  as  nearly  as  possible  the   same 
conditions    as    other    coals  we   get  a  satisfactory  practical 
knowledge  of  its  fitness  for  the  purpose.     The  disadvantages 
of  this  method  are  the  difficulty   and  expense  of  testing  a 
large  number  of  samples  in  this  way,  and  the  fact  that  since 
only  a  small  proportion  of  the  heat  can  be  obtained  in   its 
equivalent  of  steam  pressure   or   mechanical  movement,  the 
experiment  is  alwrays  a  test  of  the  efficiency  of  the  furnace 
and  boiler  and  of  skill  in  firing,  instead  of  a  determination  of 
the  absolute  value  of  the  fuel.     In  other  furnaces  or  under 
other  conditions  the  results  might  be  reversed.      It  is  only  in 
an  experimental  plant  where  all  the  factors,  such  as  the  tem- 
perature and  volume  of  the  entering  air  and  escaping  gases, 
composition  of  the  coal,  temperature  of  the  water  and   pres- 
sure of  the  steam,  losses  from   radiation,  etc.,  can   all    be 
measured,  that  the   absolute  heating  power  can   be  found. 
With  accurate  work  under  such  conditions  the  total  amount 
can  be  accounted  for  to  within  a  few  per  cent.* 

2.  Calculation  of  heating  power  from  chemical  analy- 
ses.     The  proximate  analysis  of  coal  gives,  as  may  be  seen 
from  the  tables  of  analyses  and  calorimetric  tests  in  this  bul- 
letin, a  fair  idea  of  the  relative  value,  since  of  course  the 
greater  the  amount  of  water  and  ash  the  less  the   per  cent, 
of  fuel.     No  accurate  valuation   can,  however,  be  made  on 
the  basis  of  proximate  analysis,  since  the  composition  of  the 
volatile  combustible  matter  and  even  of  the  "fixed  carbon" 


*Rowan  and  Mills:  Fuels.     Page  731. 


Womin     Coal  and  O?L 


is  not  definite  and  the  dividing  line  is  not  exact.  Elementary 
analysis  affords  a  better  basis  for  the  calculation,  and  if  the 
sample  belongs  to  a  well-defined  class  which  has  been  suffi- 
ciently studied,  the  application  of  the  proper  formula  usually 
gives  a  close  approximation  to  the  calorimetric  result.*  No 
formula  can  of  coarse  give  exact  results  because  the  ele- 
ments, carbon,  hydrogen  and  oxygen,  exist  in  compounds 
having  different  heats  of  formation  and  consequently  of  com- 
bustion. Elementary  organic  analysis  is  a  much  longer  and 
more  delicate  process  than  the  direct  determination  of  heat- 
ing value  with  the  calorimeter. 

3.  Calorimetric  tests.  The  most  satisfactory  method 
of  finding  the  heating  power  of  a  fuel  is  to  burn  a  small 
sample  under  such  conditions  as  admit  of  measuring  the 
amount  of  heat  evolved.  This  is  done  by  carrying  on  the 
combustion  inside  a  vessel  filled  with  a  known  weight  of 
water  of  a  certain  temperature.  There  are  two  kinds  of 
combustion  calorimeters;  in  one  the  fuel  is  mixed  in  a  small 
diving-bell  with  salts  such  as  potassium  chlorate  and  nitrate 
which  supply  the  oxygen,  in  the  other  it  is  burned  in  com- 
pressed oxygen. 

An  instrument  of  the  first  class,  Thompson's  calorime- 
ter, has  on  account  of  its  cheapness  and  convenience  been 
extensively  employed  in  England  and  the  United  States  in 
the  valuation  of  fuels.  The  process  is  liable  to  many  errors, 
some  of  which,  being  variable,  it  is  impossible  to  correct. 
These  errors  are  chiefly  due  to  losses  of  heat  through  the 
escaping  of  imperfectly  cooled  gases,  the -solution  of  the 
oxygrn  salts  and  their  products  in  the  water,  irregular  heat- 

*The  difference  is  about  3  per  cent.  See  a  valuable  article  by  Wm. 
Kent  on  the  heating  power  of  coal  in  The  Mineral  Industry  for  1892,  Vol. 
I,  page  97. 


20  Wyoming  Coal  and  Oil. 


ing  of  the  thick  glass  vessel,  and  particles  of  carbon  which 
are  kept  from  burning  by  the  melting  salts.  The  correction 
for  loss  of  heat  is  stated  by  the  manufacturers  to  be  TO  per 
cent.;  it  has  been  estimated,*  however,  at  30  per  cent,  and 
in  fact  no  constant  correction  can  be  used.  In  using  the  in- 
strument on  Wyoming  coals  we  found  it  necessary  to  add  a 
considerable  quantity  of  some  auxiliary  combustible  which 
complicates  the  reactions.  Even  when  it  is  constructed  for 
scientific  instead  of  technical  work  and  the  most  elaborate 
precautions  are  taken  as  in  Stohmann's  investigations^  a 
calorimeter  of  this  kind  gives  inferior  results  and  it  is  now 
abandoned  in  favor  of  the  simpler  and  more  exact  bomb 
calorimeters. 

DESCRIPTION  OF  THE  BOMB  CALORIMETER. 

The  essential  conditions  for  the  determination  of  heat 
of  combustion  are  that  the  product  be  completely  burned, 
that  the  heat  pass  entirely  into  the  water  of  the  calorimeter 
vessel  and  that  the  combustion  be  as  quick  as  possible. 
These  conditions  are  best  attained  by  the  process  devised 
by  Berthelot,  according  to  which  the  combustion  takes  place 
in  a  closed  steel  vessel  (the  so-called  bomb)  filled  with  oxy- 
gen under  twenty  to  twenty-five  atmospheres  pressure  and 
almost  entirely  immersed  in  the  water  of  the  calorimeter. 
Under  these  circumstances  a  hydrocarbon  burns  completely 
to  carbon  dioxid  and  water  in  a  few  seconds,  none  of  the 
products  of  combustion  can  escape  and  the  heat  passes  into 
the  surrounding  water  in  the  course  of  two  or  three  minutes. 
The  high  price  of  Berthelot's  calorimeter,  about  $1,500,  has 
prevented  it  from  coming  into  common  use.  In  June,  1892, 

*L.  I.  Blake:  Kansas  Academy  of  Sciences,  1888,  page  42. 
"j"Kalorimetrische  Untersuchungen   von  F.  Stohmann,  Landvvirth- 
schaftliche  Jahrbucher,  13,  page  513. 


Wyoming  Coal  ami  Oil.  21 


an  account  was  published*  of  a  modification  of  Berthelot's 
apparatus  invented  by  M.  Mahler  in  which  the  expensive 
platinum  lining  of  the  bomb  was  replaced  by  a  thin  coating 
of  enamel  without  impairing  the  efficiency  of  the  instru- 
ment.§  A  calorimeter  of  this  kind  was  procured  by  the 
University  of  Wyoming^  in  July,  1894,  for  the  study  of  the 
coal  and  petroleum  of  the  State  and  for  use  in  food  investi- 
gations in  the  Agricultural  Experiment  Station. 

As  we  have  had  many  inquiries  about  this  instrument 
and  its  workings  we  give  a  description  with  a  cut. 

The  bomb  (B  in  cut)  of  our  apparatus  is  15  centimeters 
high  and  ten  cm  in  diameter,  with  an  average  thickness  of 
eight  mm.  It  is  Martin-Siemens  soft-forged  steel  of  a  re- 
sistance of  50  kilogrammes  per  square  millimeter  of  square 
section  and  20  per -cent,  elongation.  It  is  nickel-plated  on 
the  outside  and  coated  on  the  inside  with  a  thin  white  enamel 
to  prevent  corrosion  by  the  oxygen  and  the  acids  which  are 
among  the  products  of  combustion.  The  capacity  of  the 
bomb  is  580  cc.  A  platinum  tray  (C)  of  30  mm  in  diam- 
eter and  5  mm  in  depth;};  is  suspended  from  the  cover  by  a 
rod  of  platinum.  A  similar  rod  passing  through  the  cover 
but  insulated  from  it  reaches  nearlv  to  the  tray  and  serves 
as  the  other  electrode.  The  cover  is  screwed  on  over  the 
top  of  the  bomb  and  a  hermetical  joint  secured  by  a  ring  of 

*Bulletin  de  la  Societe  d'Encouragement  pour  1'Industrie  Nation- 
ale,  Paris. 

•fT he  apparatus  is  constructed  by  M.  L.  Golaz.  Rue  Saint-Jacques, 
Paris,  and  is  sold  at  the  following  prices:  Mahler's  calorimeter  complete 
750  francs,  pump  for  compressing  oxygen  500  franc-*,  pair  of  thermometers 
50  francs.  Our  instrument  was  procured  through  Eimer  and  Amend, 
N.  Y. 

§A  cheaper  form  of  the  bomb  calorimeter  which  dispenses  with 
pump  or  gas  cylinder  is  described  in  Hempel's  Gas  Analysis. 

JThis  is  heavier  and  deeper  than  the  one  sold  with  the  apparatus. 


22  Wyoming  Coal  and  Oil. 


lead.  The  oxygen  is  passed  in  through  the  stem  of  the 
needle  valve,  which  is-  screwed  down  when  the  bomb  is 
filled.  The  bomb  is  set  in  a  support  which  touches  the 
bottom  of  the  calorimeter  vessel  on  three  points.  The  cal- 
orimeter vessel  is  a  pail  of  thin  brass,  twenty-three  centime- 
ters high  and  fourteen  centimeters  in  diameter.  This  rests 
on  three  points  of  a  light  wooden  support  and  is  surrounded 
bv  a  large  double-walled  vessel  covered  with  thick  felt  con- 
taining water  at  the  normal  temperature  of  the  room.  An 
ingenious  stirring  mechanism  enables  one  to  keep  the  water 
of  the  calorimeter  in  thermal  equilibrium  with  slight  effort. 
The  calorimeter  is  so  well  isolated  from  external  influences 
that  the  water  often  does  not  vary  in  temperature  a  hun- 
dredth of  a  degree  in  fifteen  minutes,  although  the  air  of  the 
room  may  be  quite  variable. 

Two  thermometers  were  used,  one  reading  between 
eight  and  eighteen  degrees  C.  and  the  other  between  eight- 
een and  twenty-eight  degrees;  each  degree  covering  a  space 
of  3^  centimeters.  They  are  graduated  to  a  fiftieth  of  a 
degree  and  were  read  to  one-hundredth,  although  with  a  glass 
they  can  be  read  to  a  much  finer  interval. 

The  oxygen  used  was  made  in  the  laboratory,  purified 
by  passing  through  a  solution  of  caustic  potash  and  three 
rolls  of  copper  gauze,  and  kept  in  gas-bags;  the  slight  cor- 
rection indicated  for  Berthelot*  for  the  loss  of  heat  through 
vaporization  of  water  has  not  been  applied. 

*Comptes  Rendus,  114.  p<ige  318. 


•  3   3   « 


24  Wyoming  Coal  and  Od. 


THE    PROCESS    OF    COMBUSTION. 

One  gram  of  the  coal  or  oil  is  weighed  into  the  tared 
platinum  tray  which  is  then  attached  to  the  platinum  rod  in 
the  calorimeter  bomb.  A  piece  of  iron  wire  of  known 
weight  is  stretched  across  from  the  rod  supporting  the  tray 
to  the  insulated  support  and  preferably  touching  the  com- 
bustible or  buried  in  it.  The  bomb  is  then  placed  in  a  lead- 
lined  clamp  and  the  top  tightly  screwed  on  by  means  of  a 
wrench.  The  needle-valve  is  opened  and  connected  with 
the  compression  pump  by  a  long  slender  copper  tube.  Oxy- 
gen is  then  forced  into  the  bomb  until  the  manometer  reads 
twenty  or  twenty-five  atmospheres.  The  needle  valve  is 
closed  and  disconnected  from  the  rilling  tube  and  the  bomb 
is  immersed  in  the  water  of  the  calorimeter.  The  water 
should  be  two  to  three  degrees  lower  in  temperature  than 
the  air  of  the  room  and  the  water  in  the  jacket  of  the  calor- 
imeter, and  a  sufficient  amount  should  be  weighed  out  to 
cover  the  bomb  nearly  to  the  top  of  the  insulated  electrode. 
In  our  instrument  2,309  grams  of  water  was  usually  taken, 
as  that  gave  with  the  water  value  of  the  apparatus  (491 
grams)  a  convenient  factor  for  calculation.  The  stirring 
apparatus  is  kept  in  motion  and  as  soon  as  the  change  in 
temperature  becomes  constant  readings  of  the  thermometer 
are  taken  at  intervals  of  one  minute.  At  the  end  of  the  fifth 
minute  the  combustible  is  fired  by  passing  an  electric  cur- 
rent through  the  iron  wire  raising  it  to  redness.  We  used 
a  plunge  battery  of  six  bichromate  cells  for  this  purpose 
One  wire  is  connected  to  the  insulated  electrode  and  the 
other  is  touched  to  some  exposed  part  of  the  bomb.  In 
about  ten  seconds  the  thermometer  is  observed  to  rise,  rap- 
idly at  first,  then  more  slowly,  reaching  a  maximum  usual- 
ly on  the  second  or  third  minute  after  firing  After  the 


ng  Coal  and  Oil. 


maximum  it  falls  regularly  and  slowly  if  the  proper  temper- 
ature has  been  chosen  for  the  water,  and  readings  are  again 
made  at  intervals  of  a  minute  for  five  minutes  more.  Then 
the  bomb  is  taken  out  of  the  calorimeter,  the  needle  valve 
cautiously  opened  to  allow  the  products  of  combustion  and 
residual  oxygen  to  escape;  after  which  the  bomb  is  opened 
and  rinsed  out  with  distilled  water.  The  rinsings  are  tit- 
rated with  a  standard  solution  of  potassium  hydrate  or  sod- 
ium carbonate  to  determine  the  amount  of  nitric  acid  formed 
by  the  combustion,  and  if  the  combustible  contains  sulphur 
the  solution  is  set  aside  for  determination  of  sulphuric  acid. 
The  whole  operation  including  the  weighing  of  the  sample 
and  pumping  in  the  oxygen  can  be  completed  in  less  than  an 
hour  if  everything  works  well. 

Multiplying  the  weight  of  water  taken  plus  the  water 
value  of  the  apparatus  bv  the  corrected  rise  in  temperature 
gives  the  heat  of  combustion  of  one  gram  of  the  substance, 
subject  to  the  corrections  mentioned  below. 

CORRECTIONS. 

i.  Correction  for  the  influence  of  the  temperature  of 
the  environment.  This  is  the  largest  and  most  important 
correction  to  be  made,  although  on  account  of  the  short  in- 
terval during  which  the  temperature  rises,  usually  two  min- 
utes, it  is  smaller  in  this  process  than  in  any  other. 

As  there  is  no  way  of  measuring  directly  the  amount 
of  heat  lost  or  gained  by  the  calorimeter  from  the  moment 
of  firing  to  the  moment  when  all  the  heat  of  combustion  has 
been  given  up  to  the  water  surrounding  the  bomb,  it  is  nec- 
essary to  calculate  this  from  the  rate  of  change  ot  tempera- 
ture before  firing  and  the  rate  of  change  when  the  tempera- 
ture has  come  again  to  equilibrium.  This  correction  is  most 

4— 


26  Wyoming  Coal  and  Oil. 

accurately  given  by  the  application  of  the  Regnault-Pfaund- 
ler  formula.  If  the  prelimina/v  period  and  the  final  period 
are  each  five  minutes,  with  readings  of  the  thermometer 
everv  minute,  the  correction  according  to  this  formula  is:* 

[t.-K-f-  •  •  -t...,-f^-(N-5)tJ^+(N-5)d 

where  t  indicates  the  temperature  at  the  end  of  the  minute 
designated  by  the  subscript;  t5  is  the  instant  of  firing;  N  is 
the  number  of  the  maximum  reading;  tM  is  the  average  of 
the  five  readings  before  firing;  T  is  the  average  of  the  read- 
ings of  the  final  period;  D  is  the  average  change  in  temper- 
ature during  the  final  period,  and  d  is  the  average  change  in 
temperature  during  the  preliminary  period. 

As  in  practice  the  maximum  temperature  nearly  always 
occurs  on  the  seventh,  the  eighth  or  the  ninth  moment,  the 
formula  can  be  reduced  for  these  three  cases  to  the  follow- 
ing forms,  which  are  easy  to  calculate: 

When  the  maximum  is  the  end  of  the  seventh  moment 
the  correction  for  the  loss  or  gain  of  heat  during  the  'min- 
utes 5-6  and  6-7  is 

1     /[(2t«+tT)-(2t0+t,)]   [(t7+ts)-(t0+tia)3   j         ,  , 

5  v  (tia-ft7 


When  the  maximum  is  the  eighth  moment  the  loss  or 
gain  for  the  minutes  5-6,  6-7,  7-8  is 

J_/[(2t6+2t7-ft8)  —  (3t0-}ts)  ]    [(t8+ts)—  (t,3+t0)]  _J_     /f  _f  \ 

5        ^  (t,3+t8)-(to+t8)  I       3VL0        V 

When  the  maximum  is  the  ninth  minute  the  loss  or  gain 
lor  the  minutes  5-6,  6-7,  7-8,  8-9,  is 

J^  /  [(2t»+2tT+2te+t»)-(4t0+ts)]  [(te+t6)-(t^+t0)]  _j_     /  v 

5    V  (t,*-rt.)—  (t<H-t8)  '    4\Lo     L5,' 

This  correction  becomes  a  minimum  when  the  temper- 
ature before  firing  is  rising  about  three  times  as  fast  as  it 
falls  after  the  maximum. 

*Ostwald:  Lehrbuch  der  Allgetneinen  Chemie,  2nd  Ed.,  Vol.  I, 
page  572 


Wyomino  Coal  and  Oil.  2J 


As  the  period  of  combustion  is  so  short  M.  Mahler  has 
given  a  method  of  correction  based  on  Newton's  law  which 
gives  results  sufficiently  exact  for  technical  work.  His  rules 
are:* 

1.  The  law  of  decrease  of  temperature  observed  after 
the  maximum  represents  the  loss  of  heat  before  the   maxi- 
mum and  for  any  given  minute  on  condition   that  the  mean 
temperature  of  this  minute  does  not  differ  more  than   one 
degree  from  the  maximum  temperature. 

2.  If  the  temperature  of  the   given   minute  differs  by 
more  than  one  degree  but  less  than  two  degrees  from   that 
of  the  maximum,  the  number  that  represents  the  law  of  de- 
crease at  the  moment  of  the  maximum  less  0.005   w^l   £Pve 
the  desired  correction. 

A  comparison  of  the  two  -methods  in  some  twenty 
cases  showed  an  average  difference  of  0.0013,  which  on  one 
gram  naphthalene  would  amount  to  about  three  calories,  or 
.03  of  one  per  cent.;  a  difference  within  the  limit  of  error  in 
technical  work.  In  this  bulletin  the  Regnault-Pfaundler 
formula  has  been  used  for  determining  the  constants  of  the 
apparatus  and  Mahler's  for  most  of  the  coals  and  oils. 

2.  Correction  for  j  or  mation  of  nitric  acid.  About  fifty 
milligrams  of  nitric  acid  are  formed  from  the  nitrogen  of  the 
air  by  the  combustion,  and  it  is  necessary  to  ascertain  the 
amount  of  this  and  subtract  the  heat  of  formation,  227  cal. 
per  gram,  from  the  heat  of  combustion  of  the  substance 
under  examination.  This  is  estimated  by  titration  with  a 
standard  alkali  solution  containing  3.706  grams  of  sodium 
carbonate,  Na2CO3.  One  cubic  centimeter  of  this  solution 
is  equal  to  .0044  grams  nitric  acid  of  which  the  heat  of 

*Bulletin  de  la  Societe  d'Encouragement  pour  1'Industrie  Nationale, 
June,  1892,  page  335. 


Wyoming  Coal  and  Oil. 


formation  is  one  calorie,  so  the  number  of  cubic  centimeters 
required  to  titrate  the  washings  of  the  bomb  can  be  written 
at  once  as  calories.  Methyl  orange  is  used  as  an  indicator. 

3.  Correction  for  the  combustion  of  the  iron  wire.  The 
combustion  of  the  small  piece  of  iron  wire  used  to  ignite  the 
combustible  adds  to  the  apparent  rise  in  temperature,  and 
correction  must  be  made  by  taking  a  known  weight  of  wire 
and  subtracting  its  heat  of  combustion.  A  No.  32  to  36, 
Brown  and  Sharpe  gauge,  is  suitable,  and  it  is  preferable  to 
use1  the  copper-plated  wire,  as  the  plain  wire  easily  becomes 
oxydized  on  the  surface.  Of  No.  36  wire  one  meter  weighs 
.3160  grams;  of  this  in  our  experiments  we  used  a  length  of 
4.8  centimeters,  giving  a  heat  of  combustion  ot  25  calories. 

The  heat  of  combustion  of  iron  under  these  circumstan- 
ces is  stated  to  be  1650  cal.  per  gram.*  This  is  on  the  as- 
sumption that  all  the  iron  is  burned  to  Fe,O4.  That  this  is 
not  correct  is  shown  by  the  following  analyses  of  the  iron 
oxid  resulting  from  some  twenty  combustions  each:  No.  i, 
71.59  per  cent,  iron  in  oxid;  No.  2,  75.81  per  cent,  iron  in 
oxid.  The  first  w:ould  correspond  to  74.7  Per  cent.  Fe3O4 
and  25.3  per  cent.  Fe2O3,  while  the  second  might  be  com- 
posed of  86.8  per  cent.  Fe^O4  and  13.2  per  cent,  unburned 
iron.  Other  mixtures  of  iron  and  its  oxids  would  of  course 
give  the  same  analytical  results.  The  heat  of  combustion 
of  ferric  oxid  is  not  exactly  known,  but  it  is  certainly  less 
than  that  of  Fe3O4.  It  appears  from  this  that  the  character 
of  the  oxids  formed  is  variable  and  the  ordinary  correction 
consequently  inaccurate  by  several  calories.  The  error  is 
not,  however,  as  great  as  the  analyses  would  seem  to  indi- 
cate, for  it  was  only  the  larger  particles  such  as  could  be 
easily  picked  off  that  were  taken  for  analysis. 

*Berthelot:  Traite  Pratique  de  Calorimetrie  Chiinique,  page  139. 


Wyoming  Coal  and  Oil.  29 

4.  (Correction for  sulphur.  The  presence  of  sulphur 
in  the  combustible  necessitates  another  correction,  for  the 
free  sulphuric  acid  formed  by  the  combustion  of  sulphur 
compounds  will  be  titrated  as  nitric  although  its  heat  of 
combustion  is  different  and  the  heat  of  the  burning  sulphur 
is  a  legitimate  part  of  the  heat  of  combustion  of  the  fuel. 
The  sulphuric  acid  must  therefore  be  determined  in  the  rins- 
ings of  the  bomb  after  the  titration  for  free  acid  and  the  heat 
of  formation  of  its  equivalent  in  nitric  acid  subtracted  from 
the  number  obtained  by  titration.  The  weight  of  barium 
sulphate  multiplied  by  100  gives  directly  the  number  of  cal- 
ories to  be  subtracted. 

Sulphur,  however,  exists  in  coal  in  three  forms:  organ- 
ic sulphur  compounds,  pyrites,  and  sulphates,  chiefly  gyp- 
sum. Of  these  the  third  at  least  would  not  be  converted 
into  free  acid  by  the  combustion  and  the  ordinary  correc- 
tion would  be  too  great.  The  point  is  of  especial  import- 
ance in  dealing  with  Wyoming  coals,  for  although  the  per- 
centage of  sulphur  is  generally  small  yet  it  is  more  often  in 
the  form  of  gypsum  than  pyrites.  Nevertheless,  as  to  find 
the  original  state  of  the  sulphur  would  require  two  analyses, 
the  whole  is  regarded  as  forming  sulphuric  acid  and  the 
equivalent,  usually  amounting  to  about  5  cal.,  has  been  sub- 
tracted in  all  cases. 

DETERMINATION    OF    WATER    VALUE    OF    THE    APPARATUS. 

The  heat  produced  by  combustion  is  absorbed  not  only 
by  the  water  in  the  calorimeter  but  also  by  the  calorimeter 
vessel,  the  bomb,  the  stirring  apparatus  and  thermometer  in 
contact  with  it.  But  the  amount  of  heat  absorbed  by  them 
depends  on  their  weight  and  material.  It  is  therefore 
necessary  to  find  the  water  value  of  the  apparatus,  that  is, 


jo  Wyoming  Coal  and  Oil. 

what  weight  of  water  would  absorb  the  same  amount  of 
heat  for  the  same  rise  in  temperature.  This  is  done  by 
multiplying  the  weight  of  the  different  parts  of  the  appara- 
tus by  the  specific  heat  of  the  material  of  v\7hich  they  are 
composed.*  In  this  case  the  calculation  was  as  follows: 
Calorimeter  vessel  445  g.,  stirring  apparatus  143  g., 

588  g.  brass  x  .093      -  54-69 

Bomb,  3,920  g.  steel  x  .1097  430.03 

22.36  g.  platinum  x  .0324  .72 

8  g.  lead  x  .031     -  .25 

Thermometer,  bulb  2.72  g.,  tube  33.56  g.,  ^   im- 
mersed, 8.61  g.  glass  x  .184  i'5$ 
35.36  g.  mercury  x  .033                                                1.17 
Oxygen,  (20  atmospheres  pressure)  16.7  g.  x  -i55f        2-59 

Water  value  -       491.03 

Another  method  of  determining  the  water  value  of  a 
calorimeter  is  to  burn  in  it  certain  compounds  whose  heat  of 
combustion  is  accurately  known.  This  has  the  advantage 
that  the  water  value  of  the  whole  apparatus  is  determined  di- 
rectly and  under  the  same  conditions  as  in  an  ordinary  com- 
bustion, but  it  has  the  disadvantage  that  the  heat  of  combus- 
tion of  no  compound  is  exactly  known.  In  determining  the 
water  value  of  our  calorimeter  we  made  twelve  combustions 
with  resublimed  naphthalene,  of  which  the  heat  of  combustion 
as  determined  by  Berthelotand  his  .assistants  is  9,692  calories. 
The  average  of  the  twelve  combustions  gave  491.4  grams  as 
the  water  value  of  the  calorimeter.  One  combustion  with 
granulated  sugar,  using  two  g.  and  taking  the  heat  of  com- 
bustion as  3961.7  cal.  per  gram,  gave  491  g.  as  the  value. 
As  all  these  are  in  satisfactorv  agreement  the  number  491 
has  been  adopted  as  the  water  value.  A  difference  of  one 

*The  weight  of  the  enamel  on  the  bomb  was  not  known.  The 
water  value  of  the  apparatus  as  calculated  is  therefore  too  low. 

•fStohmann  uses  .2175,  the  specific  heat  for  constant  pressure,  in- 
stead of  .155,  the  specific  heat  for  constant  volume.  Journal  fur  praktische 
Chetnie,  JJ9  page  536. 


Wyoming  Coal  and  Oil. 


gram  in  water  value  makes  a  difference  of  about  .03  of  one 
per  cent,  in  the  final  result. 

AN    EXAMPLE. 

The  method  of  calculating  the  heat  of  combustion  may 
be  made  more  dear  by  giving  in  detail  an  example  in  which 
the  corrections  are  unusually  large. 

Coal  No.  33.      L.  R.  Meyer,  Carbon.     November  30,  1894. 
i  gram  coal.     .0250  g.  wire.    2,300  g.  water  in  calorimeter. 
Preliminary  Period.        Combustion  Period.        Fi.nal  Period. 
0—11.47  5  —  11.48  9  —  13.64 

i  —  11-47  5^  —  12.50  (       10  —  13:63 

3—11.48  6—13.34  11—13.62 

4—11.48  7—13.63  12—13.62 

5  —  11.48    Fired.  8  —  13.64  13  —  13.62 

9  —  13.64  14  —  13.61 

Nitric  acid-  -9.0  cc.  sodium  carbonate  solution:  9  cal. 
Weight  BaSO4,  .0472. 

From  the  9th  to  i4th  reading  .03  deg.  heat  was  lost  or 
.006  deg.  per  minute.  Then  for  the  three  and  a  half  min- 
utes. 5>^-6,  6-7,  7-8,  8-9,  the-  total  loss  .0021  deg.  The 
temperature  rose  .01  deg.  during  the  preliminary  period 
or  .002  degree  per  minute.  The  correction  for  the  half 
minute  5-5^  is  therefore  .001.  The  total  rise  in  tempera- 
ture is  from  11.48  deg.  to  13.64  deg.  or  2.16  deg.;  adding 
to  this  the  correction  .02  deg.  gives  2.18  deg.  for  the  true 
rise  due  to  combustion.  The  water  value  of  the  apparatus, 
491  g.,  added  to  the  weight  of  water  used,  2,300  g.,  gives 
2,791  g.,  which  multiplied  by  2.18  gives  6,084.4  calories. 
The  weight  of  the  barium  sulphate  with  the  decimal  point 
moved  two  places  to  the  right  gives  4.7  to  be  subtracted 
from  9.0  cal.  leaving  4.3  cal.  The  weight  of  the  wire, 
.0250  g.,  multiplied  by  1650  gives  41.2  cal.  The  sum  of 
the  corrections  for  formation  of  iron  oxid  and  nitric  acid, 
45.5,  subtracted  from  6,084.4  gives  6,039  calories  for  the 


Coal  and  Oil. 


true  heat  of  the  combustion  of  one  gram  of  the  coal.  The 
use  of  Regnault's  formula  in  this  case  would  make  the  rise 
of  temperature  2.179  ^eg.  anc^  tne  heat  of  combustion  6,036. 

NOTES    ON    CALORIMETRY. 

The  use  of  a  cylinder  of  oxygen  under  great  pressure 
such  as  is  now  in  the  market,  dispenses  with  a  compres- 
sion pump,  and  shortens  the  time  required  for  a  combustion 
by  one-half.  It  has  the  disadvantage  that  the  quality  of  the 
oxygen  is  not  as  much  under  control  as  where  it  is  made  in 
the  laboratory. 

It  is  not  necessary  that  the  coal  should  be  finely  pow- 
dered, nor  is  there  any  difficulty  in  using  fine  samples.  Of 
the  samples  used,  one  was  in  coarse  fragments  and  some 
had  been  passed  through  a  hundred  mesh  seine.  In  using 
very  fine  coal  or  freshly  sublimed  naphthalene,  it  is  conven- 
ient to  compress  it  into  tablets  with  a  "diamond  mortar"  such 
as  is  used  in  crushing  minerals  for  analysis. 

The  cylinder  of  the  compression  pump  must  be  kept 
cool  by  a  water  jacket,  or  the  oil  will  become  ignited  by  the 
compressed  oxygen  and  an  explosion  result. 

The  rapidity  with  which  the  heat  is  given  up  to  the 
water  of  the  calorimeter  is  shown  by  the  following  average 
of  ten  determinations: 

Heat  given  off  during  the  period  5-5^-^27.9  per  cent. 


it  44  44  44 

44  44  44  44  44 


6-7  2O.  I 

7~8  _______       1.7 


IOO.O     "          '; 

That  is,  78.2  per  cent,  of  the  total  heat  is  absorbed  by  the 
water  during  the  first  minute  and  98.3  per  cent,  during  the 
first  two  minutes. 

Care  must  be  taken  to  scrape  off  the  iron  oxid  from 
the  electrodes  before  attaching  the  new  wire,  as  a  very  thin 
film  will  prevent  ignition  by  the  electric  current. 


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